1. Technical Field
The present invention relates to a common mode filter, and more particularly, to a common mode filter in which a structure of a magnetic substrate is deformed, and a method of manufacturing the same.
2. Description of the Related Art
Recently, electronic devices such as a cellular phone, a home appliance, a personal computer (PC), a personal digital assistant (PDA), a liquid crystal display (LCD), and the like, have been gradually digitalized and a speed of the electronic devices has gradually increased. Since these electronic devices are sensitive to stimulus from the outside, in the case in which small abnormal voltage and high frequency noise and introduced into the electronic devices from the outside, a circuit may be damaged or a signal may be distorted.
An example of the above-mentioned abnormal voltage and noise includes lightning, electrostatic discharge charged in a human body, switching voltage generated in the circuit, power noise included in power supply voltage, an unnecessary electromagnetic signal, electromagnetic noise, or the like. As a unit for preventing the above-mentioned abnormal voltage and high frequency noise from being introduced into the circuit, a common mode filter has been used.
Describing a general structure of a common mode filter with reference to Korean Patent Laid-Open Publication No. 10-2007-0076722, the common mode filter has a structure in which a pair of conductor coils magnetically coupled to each other is formed on a magnetic substrate and is enclosed by an insulating resin. That is, the common mode filter has a structure in which the magnetic substrate and an insulating layer are stacked when being viewed from the outside.
Therefore, external moisture permeates into an element through a space between the magnetic substrate and the insulating layer and arrives at the conductor coil to deteriorate a moisture resistance load of the common mode filter. Therefore, in order to prevent this problem, an interval between the outermost portion of the conductor coil and a side of the insulating layer, that is, a margin part has been formed to be large.
However, as the margin part becomes large, a space of the conductor coil is limited, such that a turn of the conductor coil cannot but be decreased. In this case, it is difficult to satisfy a required inductance value. This problem is gradually intensified as the common mode filter is miniaturized. Therefore, a common mode filter capable of implementing a high inductance value simultaneously with increasing a margin part, and a method of manufacturing the same have been urgently demanded.